Finned tube heat exchangers in the power industry

The application of finned tube heat exchangers in the power industry is of vital importance, mainly used in key links such as waste heat recovery, boiler systems, and gas turbine cooling. Their high-efficiency heat transfer and high-temperature and high-pressure resistance characteristics significantly enhance energy utilization efficiency. The following is a detailed analysis of its production process, specific applications and typical cases:

 

1.The production process flow of finned tube heat exchangers

The manufacturing of finned tube heat exchangers involves material selection, fin forming, tube-fin combination, assembly and inspection, etc. The power industry pays particular attention to high-temperature resistance and corrosion resistance.

1.1. Material Selection

1.1.1. Fin material:

a. Aluminum alloy (lightweight, high thermal conductivity, suitable for low-temperature scenarios, such as air preheaters).

b. Stainless steel/nickel-based alloy (high-temperature resistant and corrosion-resistant, suitable for boiler water-cooled walls and gas turbine heat exchangers).

1.1.2. Base pipe material:

a. Carbon steel (low cost, for low-pressure systems) or stainless steel/titanium alloy (high-pressure, corrosive environments).

1.2. Fin processing technology

1.2.1. Stamping Forming:

a. Aluminum/stainless steel plates are punched into fins through molds, and the height and spacing of the fins (such as flat fins, corrugated fins, and louvered fins) are controlled.

b. Key quality control points: Flange height, burrs, cracked edges, etc.

1.2.2. High-frequency Welding/Brazing:

a. High-frequency welded spiral finned tubes (low cost, welding rate ≥80%).

b. Integral extruded finned tubes (100% contact, with a heat transfer efficiency 5-6 times higher than that of smooth tubes).

1.3. Tube-wing combination technology

1.3.1. Mechanical tube expansion: Ensure that the fins are in close contact with the base tube to reduce thermal resistance.

1.3.2. Brazing: It is used for stainless steel finned tubes, which can withstand high temperatures but is relatively expensive.

1.4. Assembly and Inspection

1.4.1. Tube bundle assembly: Multiple finned tubes are arranged in bundles and fixed by tube sheets.

1.4.2. Sealing test: Pressure resistance test (such as 6MPa high-pressure detection).

2. Specific applications in the power industry

2.1. Boiler System (Water-cooled Wall and Economizer)

2.1.1. Water-cooled wall: Absorbs the radiant heat from the furnace chamber, protects the furnace wall and generates steam, and uses high-frequency welded stainless steel finned tubes.

2.1.2. Economizer: Recovers the waste heat from flue gas to preheat the boiler feed water, increasing the thermal efficiency by 12%.

2.2. Gas turbine intake cooling

2.2.1. Application: In high-temperature environments, finned tube heat exchangers are used to cool the intake air, increasing the power of gas turbines by 10% to 15%.

2.3. Waste heat Recovery of spent steam (Condenser)

2.3.1. Case: A thermal power plant adopted copper-aluminum composite finned tubes to recover the heat from spent steam, saving 12,000 tons of standard coal annually.

2.4. Compressed gas energy storage system

2.4.1. Case: In the 300MW pressurized gas energy storage power station in Yingcheng, Hubei Province, Harbin Electric Turbine adopted finned tube heat exchangers to achieve efficient heat exchange.

3. Typical Case Analysis

3.1. Petrochina Guangdong Petrochemical Project (The World's Largest Heat Exchanger)

• Scene: 800,000-ton/year styrene plant.

• Technology: Four-unit heat exchanger (finned tube + shell tube composite structure), with a heat recovery efficiency of up to 92%.

3.2. Hangzhou Oxygen High-pressure Plate-Fin Heat Exchanger (Domestic Substitution)

• Scene: Shandong Yulong Island Refining and Chemical Project.

• Breakthrough: Pressure resistance of 6MPa, cost reduction of 30%.

3.3. Jiaozuo Shijia High-frequency Welded Finned Tubes (Waste Heat Power Generation in Cement Plants)

• Effect: The annual heat recovery is equivalent to 12,000 tons of standard coal, and the reduction of CO₂ is 30,000 tons.

 

4. Future Technological Trends

4.1. Smaller pipe diameter: A 5mm pipe diameter enhances heat transfer density and reduces material usage.

4.2. Intelligent Control: Dynamically adjust heat exchange parameters in combination with PLC.

4.3. New Materials: Nickel-based alloys (Inconel) are used in supercritical units.

5. Summary

Finned tube heat exchangers have significantly enhanced energy efficiency in the power industry through applications such as waste heat recovery, boiler optimization, and energy storage support (for instance, in a certain case, the thermal efficiency was increased by 92%). In the future, with the development of materials and intelligence, its potential in high-parameter power systems will be further unleashed.

 

Related Links:

Finned tube heat exchangers in the petrochemical industry

The application of finned tube heat exchangers in refrigeration systems

How to understand finned tube heat exchangers?